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CRD 265-75-16 mileage
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Author:  jeepfam [ Wed Nov 06, 2013 12:07 am ]
Post subject:  CRD 265-75-16 mileage
Just bought an 05 CRD. Have determined the amount of lift needed to run 265 75 16 tires but am concerned with fuel mileage. I will not be re-gearing. I have searched the forum and cannot find the answer to the following question.

Can 265's increase my hwy mileage by effectively increasing the gear ratio? I assume that my rpm's would go down. And with all that awesome torque I am hoping the hwy mileage won't be affected too much.

Any experience with the CRD and 265-75-16 vs 245-75-16 would be appreciated.

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Author:  tjkj2002 [ Wed Nov 06, 2013 12:10 am ]
Post subject:  Re: CRD 265-75-16 mileage
Your going to drop both city and highway,no way around that if you don't regear with 32" tires.I'd say maybe 20mpg's on the highway.
Author:  jeepfam [ Wed Nov 06, 2013 1:00 am ]
Post subject:  Re: CRD 265-75-16 mileage
Planning on the eco tune. Will that help? Was at the tire store and just couldn't pull the trigger on the 245's. Looked so small and thin. 265's looked really good.

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Author:  tommudd [ Wed Nov 06, 2013 1:00 am ]
Post subject:  Re: CRD 265-75-16 mileage
Stick with 245-75-16s or prepare to regear
With 32s it will be turning lower RPMs which some assume will get you better mileage, but in the end it is lugging the engine, over heating the transmission
Author:  tommudd [ Wed Nov 06, 2013 1:01 am ]
Post subject:  Re: CRD 265-75-16 mileage
Regear will help
Author:  Brianawd [ Wed Nov 06, 2013 1:22 am ]
Post subject:  Re: CRD 265-75-16 mileage
I went from 27mpg mixed city/hwy, down to 25mpg mixed city/hwy. After lift and tires. 255/75/17

As Tom said you could lug the motor more. I do not feel I am luging the motor. I contribute that to the hot tune and being at peak torque most of the time between 1600-1800rpms
Author:  DOC4444 [ Wed Nov 06, 2013 7:57 am ]
Post subject:  Re: CRD 265-75-16 mileage
Almost everyone has reported a significant drop in mileage with larger tires.

DOC
Author:  OneCheekRider [ Wed Nov 06, 2013 10:49 am ]
Post subject:  Re: CRD 265-75-16 mileage
25mpg with 245/75/16 and GDE Hot tune (all GDE tunes have identical HWY fueling)
Author:  jeepfam [ Wed Nov 06, 2013 1:23 pm ]
Post subject:  Re: CRD 265-75-16 mileage
Thank you all for chiming in. I think I will stick to the 245's just to be safe. My wife ok'd the Libby based on the fuel mileage. I just sold a GTI that got 22-25mpg. Need to get close to or better than that with the liberty. I'm hoping the eco-tune gets me there.

Now the big question is load range C or E in a Duratrac. Any suggestions?
Author:  OneCheekRider [ Wed Nov 06, 2013 3:50 pm ]
Post subject:  Re: CRD 265-75-16 mileage
jeepfam wrote:
Now the big question is load range C or E in a Duratrac. Any suggestions?


I will be putting on load range C Duratracs when my current E-rated A/T set wears out. I personally don't see a need for E rated tires on my Liberty and hope the pounds saved will net better MPG
Author:  arengant [ Sun Nov 17, 2013 2:40 am ]
Post subject:  Re: CRD 265-75-16 mileage
Brianawd wrote:
I went from 27mpg mixed city/hwy, down to 25mpg mixed city/hwy. After lift and tires. 255/75/17

As Tom said you could lug the motor more. I do not feel I am luging the motor. I contribute that to the hot tune and being at peak torque most of the time between 1600-1800rpms


x2, same size tires
Author:  jtz54 [ Sun Nov 17, 2013 10:17 am ]
Post subject:  Re: CRD 265-75-16 mileage
I wish I saw this thread before I put on the 265s.
Even with eco tune hwy mileage is only 25mpg down from 27.
Next set of tires will be the 245s.
Author:  CIMARRON13 [ Sun Nov 17, 2013 2:41 pm ]
Post subject:  Re: CRD 265-75-16 mileage
I would hold off on regearing until after your lift and tires so you can see what your MPG is. I averaged 24 on highway with 245/75 MTRs and GDE eco tune. I now get 22-23 after going to 4.10 gears. My normal driving gets me 19-21 mpg now. I usually drive with traffic on the interstate (70-75mph).
Author:  arengant [ Sun Nov 17, 2013 3:02 pm ]
Post subject:  Re: CRD 265-75-16 mileage
CIMARRON13 wrote:
I would hold off on regearing until after your lift and tires so you can see what your MPG is. I averaged 24 on highway with 245/75 MTRs and GDE eco tune. I now get 22-23 after going to 4.10 gears. My normal driving gets me 19-21 mpg now. I usually drive with traffic on the interstate (70-75mph).


x2. re gear will help city driving with taller tires, and HURT highway. The stock 3.73 gears for the CRD are a little tall for highway use. If you have 32" tires and tall lift with extra weight (steel armor and such) you would be better off with 4.10's but it would only help with maybe 1-2 mpg combined.

Doing a cost analysis would be very beneficial to see how many miles you would have to drive to pay off the regear.

I know the V6 liberty's mpg increases a lot with 4.10s, but our power band is 1800-2000 rpm versus their 2600 IIRC.

If you drive flat highway above 70 mph often, I would NOT regear even with 32" tires personally.
Author:  ATXKJ [ Tue Nov 19, 2013 12:06 am ]
Post subject:  Re: CRD 265-75-16 mileage
arengant wrote:
If you drive flat highway above 70 mph often, I would NOT regear even with 32" tires personally.


x2

as I mentioned in the precurser thread to this

'when I switched - the avg of the 5 tanks before changing from 245/75/16 to 265/7516 and the average of the 5 tanks after 20.53 vs 20.51'

That was on the same drive - as do more Stop/Go driving - It gets worse - as I do more Highway it gets better and if I head back to Moab - I'll probably change tires or gears.

but right now at 70-75 - the 265's and stock gears work great.
Author:  Brianawd [ Tue Nov 19, 2013 12:26 pm ]
Post subject:  Re: CRD 265-75-16 mileage
Quote:
but right now at 70-75 - the 265's and stock gears work great.


Funny I tried to tell some people on here that a 32in tire on the crd was
Fine with out regear. They told me I was full of doo doo when I said I have
No issues with driving over the pass in overdrive. Some people just don't
Understand how well the crd does between 1600-2000rpms. Eve with my 255/75/17
I can just roll into the throttle on the pass it and it just goes.
Author:  Rixram [ Fri Nov 22, 2013 2:55 pm ]
Post subject:  Re: CRD 265-75-16 mileage
tommudd wrote:
Stick with 245-75-16s or prepare to regear
With 32s it will be turning lower RPMs which some assume will get you better mileage, but in the end it is lugging the engine, over heating the transmission


I have the 245/75/R16s and the ECO Tune and the Transmission tune, both from GDE. I went to that size from the stock 225/75/16s. I can tell you that my combo suffered very little in the way of power loss (as felt on the butt-dyno), and my mpg dropped to about 23 mpg from 24 mpg.

I can tow my 5,000 lb boat fine with this setup (I use a WD hitch, and recommend anyone else who tows over 3,500 with a Jeep do the same). I do not suffer from gear hunt in my daily driving; once I shift into 5th at 58, it holds it fine in cruise control.

I feel that were I to go to 265s, it would adversely effect the drivability of the vehicle for day-to-day.

Note: I do not have a heavy foot and I think my brakes drag a little, lowering my mileage. DOC444 has a fix for the brakes, but I've not been able to connect with him to get the prescription. (get it? Doc...prescription...)
Author:  MtnClimber [ Fri Nov 22, 2013 3:30 pm ]
Post subject:  Re: CRD 265-75-16 mileage
I'd like to know more about this fix for the brakes that DOC444 as I wonder if I have some brake drag.

I've done the feel the wheel for heat after driving a few miles and mine do not seem to heat up, but my overall mileage sucks. I only get 20mpg with the FT ECO Tune and running 245/75R16 Duratracs on Moab's. Prior to the lift and the 245's I used to get 22 - 24 mpg.

I did just invest in the GDE TCM tune so I need to see if this helps any.
Author:  CIMARRON13 [ Fri Nov 22, 2013 6:23 pm ]
Post subject:  Re: CRD 265-75-16 mileage
MtnClimber wrote:
I'd like to know more about this fix for the brakes that DOC444 as I wonder if I have some brake drag.

I've done the feel the wheel for heat after driving a few miles and mine do not seem to heat up, but my overall mileage sucks. I only get 20mpg with the FT ECO Tune and running 245/75R16 Duratracs on Moab's. Prior to the lift and the 245's I used to get 22 - 24 mpg.

I did just invest in the GDE TCM tune so I need to see if this helps any.

What load range are your Duratracs? My MTRs are E which defiantly affects my MPG. Since my CRD doesn't see the dirt has much since I have the Land Cruiser I will be dropping to a D range tire next time. My f350 gets the towing duties as well.
Author:  MtnClimber [ Fri Nov 22, 2013 9:21 pm ]
Post subject:  Re: CRD 265-75-16 mileage
My Duratracs are the C load range that i run at 35psi.
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